Gordon Ramsay has been no stranger to bad news in the last couple of years. His restaurant empire has faltered; he has been accused of torrid sexual wrongdoings; former proteges have turned against him.

Through it all, the two central relationships in his life have appeared to stand firm: that to his wife, Tana, and to his father-in-law and business partner, Chris Hutcheson. Last week, however, the second of these was shown to be less resilient than was thought when it was announced that Hutcheson had left his position as CEO of Gordon Ramsay Holdings Ltd.

It isn't yet clear what caused the rupture (all we know is that it followed a blazing row) but the implications for Ramsay cannot be anything other than extremely worrying. More than any other setback to have befallen the Glasgow-born chef in recent times, this one surely casts severe doubts over his future. It isn't much of a secret that Hutcheson has been integral to Ramsay's meteoric rise over the last 12 years, acting as his adviser, role model and even surrogate father, and effectively overseeing the day-to-day running of the business while Ramsay was busy turning himself into a TV celebrity.

It could be argued that Ramsay is now big enough (and rich enough) to flourish without his former mentor. After all, after a rocky patch following the credit crunch his business is no longer in the red financially (it posted impressive profits of £4.2m in the 11 months leading up to August) and he'll no doubt be able to find someone else to run it for him. Moreover, his fame won't disappear overnight.

The truth, though, is a bit more complex. Ramsay's success has always rested on a delicate balance between three things: his reputation as a chef; his acumen (aided by Hutcheson) as a businessman; and his fame as a TV personality. The three have reinforced each other in a sort of virtuous circle; remove any one from the equation, and it's hard to see how the other two would survive.

Ramsay's greatest current difficultly, arguably, is that, although he is still doing well in purely financial terms, the other two prongs of his success – his culinary reputation and fame – are beginning to look somewhat tarnished. The reputation of his restaurants is no longer what it was. Back in the early 2000s his flagship Royal Hospital Road restaurant was rightly seen as the most exciting place to eat in London, if not Britain. In the newly published 2011 Harden's guide to London's restaurants, it is ranked just 17th.

In addition to his own (much neglected) skills in the kitchen, Ramsay's other great strength has always been his ability to discover and nurture talent. But his two most brilliant proteges – Marcus Waering and Angela Hartnett – are no longer with him. Restaurant empires are ultimately propped up by the chefs, and Ramsay's, these days, seems worryingly lacking in this respect.

And while he remains very much a presence on our TV screens, there is evidence that here, too, the Ramsay shtick is starting to wear thin. People have grown tired of his all-swearing, tough-guy persona. But his attempts to convince us that, beneath the bluster, he is really a kind soul – the subtext of his voyage of discovery round India in Gordon's Great Escape this year – have so far proved unconvincing. Nor does his latest series, Ramsay's Best Restaurant, based on a segment from his magazine show The F-Word, seem set to revive his reputation: in both critical and audience terms, it has so far met with an unenthusiastic response.The one thing we can be certain of about Ramsay is that his will to succeed is incredible, and it is much too early to write him off. But without Hutcheson these will be severely testing times for him both professionally and personally. Those close to him may have to get used to a lot more swearing.